size comparisons of stars etc

[proflight2000]

Can anyone point me in the direction of a web site which gives comparisons of star sizes etc, I looked at a couple of videos yesterday on youtube where it showed the size of the earth compared to the sun, then the size of the sun compared to say Acturus and so on, trouble is the video did not last too long so I would be interested in looking at some web stuff, more out of interest than anything else.

I did find this http://en.wikipedia.org/wiki/List_of_largest_stars but picture comparisons would be nice

[proflight2000]

Ahh found this google video that may give an idea http://video.google.com/videoplay?docid=-3974466981713172831&sourceid=Himself just need to ask the question why do we not get heat from these massive big stars, especially when they are compared to the size of the sun, Sirius for instance, does it have the ability to provide heat to the earth. Odd question I know.

Just out of interest, this video http://video.google.com/videoplay?docid=1149534259046443854 is pretty good, the quality isnt great but good graphics etc.

[themos]

Look at the video in this topic :

http://stargazerslounge.co.uk/index.php?topic=11741.0

[Kaptain Klevtsov]

just need to ask the question why do we not get heat from these massive big stars, especially when they are compared to the size of the sun, Sirius for instance, does it have the ability to provide heat to the earth. Odd question I know.

We do get heat from all the stars according to how much of the sky they fill up. If you imagine a glass cover over the earth about rooftop height with a spark on it, that's a lot more than you get from a star. The size of the star as you look up at it, if you drew round it on the glass cover, would be about 0mm across.

Because of the enormous distances involved each star has essentially no angular size, so even though it is enormously hot, the heat that we get is negligible.

Because the sun is so much closer to us, it does have an angular size, so if you drew round it on the imaginary glass cover you would have a dimension. Replace the sun with a disc to fit where you drew round the sun, heat the disc to the sun's surface temperature (really really hot) and you would recreate the heat from the sun almost exactly.

HTH

Captain Chaos

[lunator]

PF2000

CC is quite right the Stars are too far way to provide heat to us. Although the Ancient Eyptians did believe Sirius added to the heat of Summer.

Cheers

ian

[proflight2000]

Thanks CC, I have been looking at the shear size of some of these stars and to think how big they are compared to the sun is awesome. I was going to see if it was possible to locate the VY Canis Majoris, I now have this listed in my book but on starry night its just a speck in the distance